broadwell. she is his biographer. broadwell spent a year with petraeus in afghanistan interviewing him for the book she co-wrote about him. it's not clear whether broadwell is the woman with whom petraeus has admitted to having this affair that led to this resignation. the official says that the fbi counterintelligence unit investigated the tip to see if there was a potential security risk, whether petraeus could possibly be blackmailed. the official tells cnn there was no suggestion the fbi was investigating petraeus for any possible wrongdoing, but the concern, rather, was that he might be putting himself in a vulnerable position. >> we know that a lot of the questions from online that i've read, some of the comments on cnn.com, there's questions about the timing. let's start with what it comes after, the presidential election. what if we found out about that connection, if any, and why this comes just days after the election? >> reporter: well, that's a great question and i think a lot of tho